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<title>Hazards: Secondhand Smoke May Affect Hearing</title>
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Researchers, writing in the July issue of The Archives of Otolaryngology — Head and Neck Surgery, tested more than 2,000 teenagers for cotinine, an indicator of exposure to tobacco smoke. After eliminating smokers from the study, they were left with 799 nonsmokers whose cotinine levels indicated exposure to secondhand smoke, along with 754 who were not exposed to cigarette smoke.        </p><p>
After controlling for many variables they found that the higher the cotinine level in a participant’s blood, the greater the likelihood there was some type of hearing loss. More than 17 percent in the highest quartile for cotinine levels had hearing loss at low frequencies.        </p><p>
It is unclear exactly how exposure to secondhand smoke could cause the damage, but tobacco is known to affect blood flow through the smallest blood vessels, the kind the inner ear depends on        </p><p>
“Most kids, about 85 percent, were unaware of their hearing loss,” said Dr. Anil K. Lalwani, the lead author of the study. “You can’t rely on self-reports.”        </p>
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